I have been struggling with this problem for a couple of months now. It is a 912ULS, vintage 2010. 300 hr. It has the yellow ignition modules.
At first the not shutting off was intermittent, and when cold. Now it is consistent. It is the A module, and I have swapped connectors to confirm, and tested both P leads and ignition switch repeatedly, without being able to find a fault. I even went so far as to stuck a pin through the brown ground lead as it enters the module, still showing continuity to ground. I sent the modules to Lockwood for testing, and they insist they are working properly. if you test the B module you get a resistance reading when you test the brown lead to some of the other leads from the connector. Not so with the A module. Am I proving Lockwood wrong or is there something I'm missing? Before I shell out the $1000 for a new module, I wanted to take one last ditch effort to find out if others have experienced this.
Thanks! Dave L